This invention relates to fluid displacement apparatus, and in particular, to fluid compressor units of the scroll type.
Scroll type apparatus has been well known in the prior art as disclosed in, for example, U.S. Pat. No. 801,182 and others, which include two scroll members each having an end plate and a spiroidal or involute spiral element. Scroll members are maintained angularly and radially offset so that both of the spiral elements interfit so as to maintain a plurality of line contacts between the spiral curved surfaces to thereby seal off and define at least one fluid pocket. The relative orbital motion of scroll members shifts the line contacts along the spiral curved surfaces and, therefore, the fluid pocket changes in volume. The volume of the fluid pocket increases or decreases dependent on the direction of the orbital motion. Therefore, scroll-type apparatus is applicable to compress, expand or pump fluids.
In comparison with conventional compressors of the piston type, a scroll-type compressor has advantages such as a lesser number of parts, continuous compression of fluid and others. However, there have been several problems: primarily; sealing of the fluid pocket, wear on the spiral elements, and inlet and outlet porting.
Although many patents, for example, U.S. Pat. Nos. 3,884,599, 3,924,977, 3,994,633, 3,994,635, 3,994,636 have attempted to resolve those and other problems, the resultant compressor is complicated in construction and in production. Furthermore, because a plurality of spaced radial bearings are used to support a drive shaft, the axial length of the drive shaft is increased so that the resultant compressor is increased in total length, in volume and in weight.
In the compressor of this type, it is desired that any deflections and undesired vibrations of moving parts be prevented by simple construction. And it is also desired that the mechanism for preventing the orbiting scroll member from rotating be simple and compact.